<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>浮动</title>
    <style >
        .box{
            width: 620px;
            height: 220px;
            border: 1px solid #000;
        }
        .box .c1{
            width: 400px;
            height: 200px;
            background-color: aqua;
            float: left;
        }
        .box .c2{
            width: 200px;
            height: 100px;
            background-color: #ff5569;
            float: left;

        }
        .box .c3{
            width: 200px;
            height: 100px;
            background-color: #88ff3c;
            float: left;

        }
    </style>
</head>
<body>
        <div class="box">
            <div class="c1">1</div>
            <div class="c2">2</div>
            <div class="c3">3</div>
        </div>
</body>
</html>
